The present invention relates to a steel laminate gasket with a seal protecting member for protecting creep relaxation of sealing means formed around a hole of the engine.
A gasket is installed between two engine parts to seal areas around holes of the engine parts. In order to securely seal around the holes, the gasket is provided with sealing means around the holes, which provides high surface pressure when the gasket is tightened.
When an engine operates, the engine together with the gasket vibrates. Although the engine parts are securely tightened by bolts, when the engine vibrates, the gasket vibrates or is compressed repeatedly in accordance with vibration of the engine. Especially, the outer periphery of the engine vibrates severely.
In a cylinder head gasket, since bolts are arranged to securely and equally compress sealing means around cylinder bores, the sealing means around the cylinder bores are not substantially damaged by vibration of the engine. However, other holes, such as water holes and oil holes, are not equally compressed by the bolts, so that the sealing means around the other holes are liable to be damaged.
When the gasket is used for a long period of time, creep relaxation may occur at the sealing means around the other holes to thereby cause leakage of fluid.
In a steel laminate gasket, in case one of plates is provided with a bead around a hold to be sealed, a pressure regulation plate may be situated outside the bead so that the bead is not completely compressed when the gasket is tightened.
However, there is no means for partly changing surface pressure around a bolt when a gasket is tightened.
Accordingly, one object of the present invention is to provide a steel laminate gasket, which can partly change surface pressure around a bolt when a gasket is tightened.
Another object of the invention is to provide a steel laminate gasket as stated above, which can regulate surface pressure around a hole to be sealed and prevent creep relaxation of sealing means around the hole.
A further object of the invention is to provide a steel laminate gasket, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.